Engagement is an important factor for social media platforms [1]}, [2]} as for education [3]}. The CWB-RS must prevent students from “dropping out” [4]}, [5]} and moving to other non-educational social media interfaces. In a complementary manner to the game-oriented motivational mechanisms of the Companion [6]}, the CWB-RS must therefore preserve a healthy level of engagement [7]}, [8]}, [9]}, [10]}. However, unlike the traditional recommender systems for social media, it must avoid excessive exposure to toxic content as well as any form of addictive use [11]}, [12]}, [13]}.
